This invention relates to the field of the detection of drug use by immunoassay testing of bodily fluids. More particularly the invention relates to the search for reagents which will provide sensitive, specific and reproducible performance in the context of microparticle based immunoassay formats. There is a widely acknowledged need for improvements in such assays for detecting both drugs of abuse and therapeutic agents.
In immunoassay approaches for the detection of drugs, various parent drugs, drug metabolites, as well as synthetic drug derivatives, have been explored as haptenic starting points for the development of one or more reagents in various assay systems. These various compounds have exhibited their own advantages and disadvantages when employed as haptens per se, or when used in, or when further modified for use in, specific immunoassay formats.
The use of such compounds as haptenic ligands in microparticle based immunoassays, i.e., linked to a microparticle substrate in a variety of systems, has also been explored. Usually, these systems have as their goal the enhancement of the speed, specificity and, most importantly, the detection of the ultimate interaction or competition of the microparticle bound ligand with the antibody or drug present in a sample.